The Mayan calendar did not account for Leap Year, no, so if the world were supposed to end it would have happened 7 months ago. 12/21/12 is just another normal day except it is the Winter Solstice. Don't be alarmed when the sun doesn't rise until 9 am and sets at 3 pm, because it is the shortest day of the year and it's supposed to do that.
Dint worry it's fake. Just turn it into a joke and you won't even notice it. For example, I'm going to have my friend over and we are going to call people and wish them happy doomsday and then watch the Doctor Who episode called Doomsday. And on Saturday I will think: well, that was the best Doomsday I've ever had :)
If no one ever told you how old you are, How old would you be? In the first place you are much younger then you have been told you are. Would you believe that in some places they don't use a calendar. The Mayan's left and no one knows where they went. Some day it will be your turn. It's a good thing.